package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.*;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *

 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;
    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;


    /**
     * 查询热门博客
     * @param current
     * @return
     */
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->{
            queryUserByBlog(blog);
            isBlogLiked(blog);
        });

        return Result.ok(records);
    }


    /**
     * 根据id查询博课信息
     * @param id
     * @return
     */
    @Override
    public Result queryBlogById(Long id) {
       //查询博课信息
        Blog blog = this.getById(id);

        if (Objects.isNull(blog)) {
            return Result.fail("笔记不存在");
        }
        //查询blog相关的用户信息
        queryUserByBlog(blog);
        //判断当前用户是否点赞过该博客
        isBlogLiked(blog);
        return Result.ok(blog);

    }

    /**
     * 判断当前用户是否点赞过该博课
     * @param blog
     */

    private void isBlogLiked(Blog blog) {
        //获取当前登录的用户
        UserDTO user = UserHolder.getUser();

        if(user == null){
            //用户未登录无需查询是否点赞
            return ;
        }
        Long userId = UserHolder.getUser().getId();
        String key = BLOG_LIKED_KEY + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score!=null);
    }

    /**
     * 点赞逻辑
     * @param id
     * @return
     */
    @Override
    public Result likeBlog(Long id) {
        //1.获取登录的用户
        Long userId = UserHolder.getUser().getId();
        //2.判断当前用户是否已经点赞
        String key = BLOG_LIKED_KEY + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());

        if(score == null){
            //3. 如果未点赞，可以点赞，数据库点赞数加一
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            
            if(isSuccess){
                //保存用户到redis的set集合
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
            
        }else{
            //4. 如果已点赞，则取消点赞，数据库点赞数减一
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            //从set集合中移除，下次就可以点赞了
            if(isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }

        }
        return Result.ok();
    }

    /**
     * 点赞列表查询
     * @param id
     * @return
     */
    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        //1.查询top前五的点赞用户 zrange key 0 4
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5 == null||top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        //2.解释其中的用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());

        String idStr = StrUtil.join(",", ids);
        //3.根据用户id查询用户 WHERE id IN (5,1)
        List<UserDTO> userDTOS = userService.query().in("id", ids)
                .last("ORDER BY FIELD(id," + idStr + ")").list()
                .stream().map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        //4.返回
        return Result.ok(userDTOS);
    }

    /**
     *  根据id查询博主的探店笔记
     * @param current
     * @param id
     * @return
     */
    @Override
    public Result queryBlogByUserId(Integer current, Long id) {
        //根据用户的id进行分页查询
        Page<Blog> page = query().eq("user_id", id)
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));

        List<Blog> records = page.getRecords();
        // 获取当前页数据
        return Result.ok(records);
    }

    @Override
    public Result saveBlog(Blog blog) {
        // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店博文
        boolean isSuccess = this.save(blog);
        if(!isSuccess){
            return Result.fail("保存博客笔记失败");
        }
    //查询发布该笔记作者的所有粉丝 select * from tb_follow where follow_user_id = userId
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        //推送该笔记给所有粉丝
        for (Follow follow : follows) {
            //获取粉丝的id
            Long userId = follow.getUserId();
            //推送
            String key = FEED_KEY + userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }

        // 返回id
        return Result.ok(blog.getId());
    }

    /**
     *分页查询关注用户的博课
     * @param max
     * @param offset
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1.获取当前登录的用户
        Long userId = UserHolder.getUser().getId();
        //2.查询收件箱,zrevrangebyscore key max min limit offset count
        String key = FEED_KEY + userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        //3.非空判断
        if(typedTuples == null || typedTuples.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        //4.解析数据，blogId,minTime,offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0; // 本次查询到的最小时间戳（用于下一次分页）
        int os = 1; // 下一次查询的偏移量

        for (ZSetOperations.TypedTuple<String> tuple : typedTuples) {
            //4.1获取博客id
            ids.add(Long.valueOf(tuple.getValue()));
            //4.2获取分数(时间戳)
            long time = tuple.getScore().longValue();

            if (time == minTime) {
                os++;
            } else {
                minTime = time;
                os = 1;
            }

        }
        // 最终确定下一次查询的偏移量
           os = minTime == max ? os : os + offset;
            //5.根据id查询博客
            String strIds = StrUtil.join(",", ids);
            List<Blog> blogs = query().in("id", ids)
                    .last("ORDER BY FIELD(id," + strIds + ")").list();

            for (Blog blog : blogs) {
                //查询blog相关的用户信息
                queryUserByBlog(blog);
                //判断当前用户是否点赞过该博客
                isBlogLiked(blog);
            }

            ScrollResult result = new ScrollResult();
            result.setList(blogs);
            result.setMinTime(minTime);
            result.setOffset(os);
            return Result.ok(result);
    }

    /**
     * 查询博客相关用户的信息
     * @param blog
     */
    private void queryUserByBlog(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }
}
